An estate agent doesn't have to be registered to practice, although many are registered with the National Association of Estate Agents (NAEA) and the Ombudsman for Estate Agents (OEA). This means they have to abide by a code of practice.
All estate agents are bound by the Estate Agents Act, whether or not they are registered with a governing body.
If you have a complaint about the conduct of an estate agent you can contact the OEA.
The OEA provides an independent service for dealing with disputes between estate agents who are members of the Ombudsman Scheme, and consumers who are actual, or potential buyers or sellers of residential property in the UK.
The OEA will advise on alternative routes to take if the estate agent you wish to complain about is not a member. You can also contact the council's trading standards department.
National Association of Estate AgentsOmbudsman for Estate AgentsCitizens Advice BureauThe Office of Fair Trading: Using an estate agent to buy or sell your homeEstate Agents Act